Paul.....You can see solid stationary objects in the Altgens photo that also appear on the plat. The concrete pylon. the street light and the TSBD are objects that were / are ANCHORED to a known location. It's a POC to see that the west corner of the concrete pylon aligns with the center of the third window from the SE corner, of the TSBD .... That's just like aiming a rifle Paul...... Rear sight with front sight ..... You can draw a line from the center of that third floor window through the west corner of the pylon and on to the triple underpass . (Elsie Dorman was behind the third window on the fourth floor and her name is written on the plat) Since the hood ornament of the movable object ( the Lincoln) falls on that line you can locate that car on the plat and you can locate Altgens by drawing a line from the east side of the fourth window through the street light and on to the triple underpass.....The point that those two lines meet is the spot where Altgens was standing when he snapped the photo.